Rock tumblers are used to smoothen the rough surface of rocks. We can find smooth stones in rivers and streams, which are formed as a result of the geological tumbling process. The flow of water makes the stones in rivers and streams collide with sand, water, and other stones, and gradually, make their surfaces smooth.
This process can be emulated to produce smoothened stones by using rock tumblers; they use the same mechanism of the natural process to smoothen their surfaces. They require various materials or supplies to yield the end product. These include:
Usually, the ones used in general include quartz, jaspers, agates, and flints. They do not have empty spaces and have grainy textures. As sandstone, shale, schists, and siltstone are fragile, they are unable to withstand this process.
Limestone and dolomite do acquire a smoothened surface after tumbling. However, they do not acquire gloss. Thus, it is important that you identify the ones to be used, before you start with the process. Do not use different types of rocks together.
It is a mixture in the rock tumbler that is harder than rocks and promotes their abrasion. In commercial rock tumblers, the grit is made up of silicon carbide. When the rocks tumble, they come in contact with this grit, and abrasion takes place. Different grits are used at different stages of this process.
The different sizes include coarse (60/90), medium (120/200), and fine (500). The coarseness of the sand is graded by the unit grit. Smaller the number that represents the grit, coarser is the silicon carbide.
Coarse grit is used in the initial phase, while fine grit, a powder-like sand, is used during the last stage to polish the stones. The mechanism of abrasion by grit is similar to that achieved by a sandpaper.
Rock Polish or Pre-polish
Once they are tumbled, they are to be polished to produce a glossy look. This step is necessary to give a lustrous finish to the tumbled stones. There are various chemicals used for polishing. These stones include oxide products like tin oxide, cerium oxide, and aluminum oxide.
They include materials like pellets and beads that are mixed with the grit. They are included to avoid chipping, cracking, or breakage of rocks caused due to frequent tumbling. They act as cushions between them. The tumbling media, usually used in this process, include small hardwood pieces, ceramic beads, and plastic pellets.
- Clean the container and the stones every time you change the grit.
- Ensure that you clean each stone separately while changing it.
- Do not fill the water completely with grit, as this may not produce good results.
- Regular maintenance of the tumbler assembly that includes motor and other mechanism is essential.
- If you find any stone that is cracked or damaged, remove it.
- Do not drain the used grit in sinks as your sink may get blocked.
- Use similar types of rocks (small-sized) while tumbling. Make batches of these types, and tumble them separately.
You can make your own rock tumbler, and use these stones for many purposes. A lot of innovative ideas can be implemented with the final product. This process is indeed lengthy, and needs a lot of patience. It is important that you use appropriate supplies to get smooth and polished stones.